Bioaccumulation, trophic transfer, and health risk assessment of microplastics in the food web of Wuliangsuhai Lake, China: Higher risk for children

Microplastics (MPs) are widely ingested by aquatic organisms. Thus far, our understanding of the biomagnification potential and health risks of MPs in lake ecosystems remains unclear. Herein, we investigated the pollution levels and characteristics of MPs in surface water, sediment, and aquatic organisms from Wuliangsuhai Lake, China. Food web structure was determined by stable isotope analysis, then the biomagnification potential and associated human health risks of MPs were assessed. The dominant shape of MPs in Wuliangsuhai Lake was fiber, with particle sizes mainly less than 0.5 mm, the primary colors were transparent and blue, and the main polymer types were polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP). MP concentrations in organisms decreased with the increasing body size, and the concentration of MPs in omnivorous organisms was significantly higher than that in organisms with other feeding strategies. A significant negative correlation was observed between the trophic level of organisms and their MP concentration, indicating that biodilution of MPs occurred in the food web. PP exhibited a higher biodilution effect while PET showed a lower biodilution effect. MPs were accumulated in the edible tissues (e.g., muscle) of aquatic organisms, indicating the human health risk via the dietary route of consuming MP-contaminated aquatic products. Notably, the estimated daily intake (EDI) of MPs for children was higher than that for adults, highlighting the greater health risks for children. This study provided new insights into the trophic transfer and the associated health risks of MPs in lake ecosystems. Future research should investigate the trophic transfer of nanoplastics along the food web to assess their potential risks to human health.